/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the  "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id$
 */
package wx.xml.xalan.xalan.templates;

import javax.xml.transform.TransformerException;

import wx.xml.xalan.xalan.transformer.TransformerImpl;
import wx.xml.xalan.xpath.VariableStack;
import wx.xml.xalan.xpath.objects.XObject;

/**
 * Implement xsl:param.
 * <pre>
 * <!ELEMENT xsl:param %template;>
 * <!ATTLIST xsl:param
 *   name %qname; #REQUIRED
 *   select %expr; #IMPLIED
 * >
 * </pre>
 *
 * @xsl.usage advanced
 * @see <a href="http://www.w3.org/TR/xslt#variables">variables in XSLT Specification</a>
 */
public class ElemParam extends ElemVariable {
    static final long serialVersionUID = -1131781475589006431L;
    int m_qnameID;

    /**
     * Constructor ElemParam
     */
    public ElemParam() {
    }

    /**
     * Copy constructor.
     *
     * @param param Element from an xsl:param
     * @throws TransformerException
     */
    public ElemParam(ElemParam param) throws TransformerException {
        super(param);
    }

    /**
     * Get an int constant identifying the type of element.
     *
     * @return The token ID of the element
     * @see wx.xml.xalan.xalan.templates.Constants
     */
    public int getXSLToken() {
        return Constants.ELEMNAME_PARAMVARIABLE;
    }

    /**
     * Return the node name.
     *
     * @return The element's name
     */
    public String getNodeName() {
        return Constants.ELEMNAME_PARAMVARIABLE_STRING;
    }

    /**
     * This function is called after everything else has been
     * recomposed, and allows the template to set remaining
     * values that may be based on some other property that
     * depends on recomposition.
     */
    public void compose(StylesheetRoot sroot) throws TransformerException {
        super.compose(sroot);
        m_qnameID = sroot.getComposeState().getQNameID(m_qname);
        int parentToken = m_parentNode.getXSLToken();
        if (parentToken == Constants.ELEMNAME_TEMPLATE
            || parentToken == Constants.EXSLT_ELEMNAME_FUNCTION)
            ((ElemTemplate) m_parentNode).m_inArgsSize++;
    }

    /**
     * Execute a variable declaration and push it onto the variable stack.
     *
     * @param transformer non-null reference to the the current transform-time state.
     * @throws TransformerException
     * @see <a href="http://www.w3.org/TR/xslt#variables">variables in XSLT Specification</a>
     */
    public void execute(TransformerImpl transformer) throws TransformerException {
        if (transformer.getDebug())
            transformer.getTraceManager().fireTraceEvent(this);

        VariableStack vars = transformer.getXPathContext().getVarStack();

        if (!vars.isLocalSet(m_index)) {

            int     sourceNode = transformer.getXPathContext().getCurrentNode();
            XObject var        = getValue(transformer, sourceNode);

            // transformer.getXPathContext().getVarStack().pushVariable(m_qname, var);
            transformer.getXPathContext().getVarStack().setLocalVariable(m_index, var);
        }

        if (transformer.getDebug())
            transformer.getTraceManager().fireTraceEndEvent(this);
    }

}
